A Randomized Trial of Alerting to Low Glycated Hemoglobin Level in Older Adults: Results of the Low Indexes of Metabolism Intervention Trial B (LIMIT-B)

Objectives: The benefit of alerting clinical staff to low plasma glycated hemoglobin (HbA1c) in patients aged 75 years and older who receive antidiabetic drugs remains uncertain. Design, Setting, and Participants: In a randomized controlled trial, 1684 patients with HbA1c ≤ 6.5% who received antidiabetic drugs were assigned to have an e-mail alert sent to their physician, and 1643 were assigned to have no such alert (control group). The primary outcome of the trial was annual death. Secondary outcomes included antidiabetic drug dose reduction and HbA1c change. Results: In the first quarter, antidiabetic drug-defined daily doses were reduced on average by 10.4 ± 35.8 (16% ± 55%) in the intervention group and by 6.4 ± 36.1 (10% ± 56%) in the control group (difference −4.1 ± 1.2, 95% confidence interval [CI] −6.5 to −1.6; P = .001). Measured HbA1c levels were raised by a mean (± standard deviation) of 0.28 ± 0.77 in the intervention group and by 0.18 ± 0.57 in the control group (difference 0.10 ± 0.02, 95% CI –0.15 to −0.059, P < .001). One year after the alerts, 121 patients (7.2%) died in the intervention group and 107 patients (6.5%) died in the control group (relative risk 1.1, 95% CI 0.86-1.42; P = .44). Conclusions and Implications: In this trial, alerting clinical staff to low HbA1c in patients aged 75 years and older treated with antidiabetic medicines was associated with mildly reduced antidiabetic doses and increased HbA1c but was not associated with a significant difference in survival rate compared with usual clinical care.